Editor's note: David Gergen is a senior political analyst for CNN and has been an adviser to four presidents. He is a professor of public service and director of the Center for Public Leadership at Harvard University's Kennedy School of Government. Follow him onTwitter. Michael Zuckerman is his research assistant.
(CNN) - Space Shuttle Discovery started out as a way to discover what lies beyond us. Its last flight, taken earlier this week, helped to discover what now lies within us.
Piggybacked atop a specially outfitted 747, Discovery made its flyover Tuesday above Washington - soaring over the White House and the Capitol, the Washington Monument and Arlington National Cemetery - en route to Dulles Airport and its new (and final) home, the National Air and Space Museum's Udvar-Hazy Center.
All around Washington, people climbed up on rooftops, pulled off to the side of the road or gathered anywhere with a clear view to watch the shuttle's parting journey. The Washington Post reported tens of thousands on the Mall alone.